System and method for restricting mobility in wireless networks

ABSTRACT

This invention provides a method, system and apparatus for controlling mobility on a wireless network, which includes retrieving a network mobility preference, the network mobility preference indicating a level of mobility service for the mobile station, the level of mobility service indicating the extent to which the mobile station can handoff among base stations of the wireless network, and establishing a level of mobility service for the mobile station based on the retrieved network mobility preference. The method and apparatus may further include determining the level of mobility service for the mobile station to be fully or partially restricted based on the mobility preference.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.11/634,775, filed Dec. 6, 2006, now U.S. Pat. No. 8,086,235, entitledSYSTEM AND METHOD FOR RESTRICTING MOBILITY IN WIRELESS NETWORKS, theentirety of which is incorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

n/a

FIELD OF THE INVENTION

The present invention relates to communication networks, and moreparticularly to a method and apparatus for controlling mobility of amobile station in a wireless communication network.

BACKGROUND OF THE INVENTION

As the demand for high speed broadband networking over wirelesscommunication links increases, so too does the demand for differenttypes of networks that can accommodate high speed wireless networking.For example, the deployment of Institute of Electrical and ElectronicsEngineers (“IEEE”) 802.11 wireless networks in homes and business tocreate Internet access “hot spots” has become prevalent in today'ssociety. However, these IEEE 802.11-based networks are limited inbandwidth as well as distance. For example, maximum typical throughputfrom a user device to a wireless access point is 54 MB/sec. at a rangeof only a hundred meters or so. In contrast, while wireless range can beextend through other technologies such as cellular technology; datathroughput using current cellular technologies is limited to a fewMB/sec. Put simply, as the distance from the base station increases, theneed for higher transmission power increases and the maximum data ratetypically decreases. As a result, there is a need to support high-speedwireless connectivity beyond a short distance such as within a home oroffice.

As a result of the demand for longer range wireless networking, the IEEE802.16 standard was developed. The IEEE 802.16 standards are oftenreferred to as WiMAX or less commonly as WirelessMAN or the AirInterface Standard. These standards provide specifications for fixedbroadband wireless metropolitan access networks (“MAN”s) that use apoint-to-multipoint architecture (IEEE 802.16d) and combined fixed andmobile broadband wireless access system's (IEEE 802.16e). Suchcommunications can be implemented, for example, using orthogonalfrequency division multiplexing (“OFDM”) communication. OFDMcommunication uses a spread spectrum technique distributes the data overa large number of carriers that are spaced apart at precise frequencies.This spacing provides the “orthogonality” that prevents the demodulatorsfrom seeing frequencies other than their own.

The 802.16 standards support high bit rates in both uploading anddownloading from a base station up to a distance of about 30 miles(about 50 km) to handle such services as VoIP, IP connectivity and othervoice and data formats, e.g., time division multiplexing (“TDM”).Expected data throughput for a typical WiMAX network is 45 MBits/sec.per channel. The 802.16e standard defines a media access control (“MAC”)layer that supports multiple physical layer specifications customizedfor the frequency band of use and their associated regulations. This MAClayer uses protocols to ensure that signals sent from different stationsusing the same channel do not interfere with each other and “collide”.

The IEEE 802.16e air interface standard and corresponding WiMAX networkarchitecture standard, as defined by the WiMAX forum, is primarilydesigned to support user/device mobility. Some network operators havereadily available radio spectrum for deploying an 802.16e network;however, governmental regulations may restrict usage of these radiospectrums for supporting mobile wireless devices. In other words,although a network is fully compliant with the IEEE 802.16e standard andcapable of supporting full mobility services for mobile wirelessdevices, government regulations require that the mobility services beeither partially or completely restricted or unavailable to the wirelessdevices. It is therefore desirable to have methods and systems toprevent full or partial mobility support for IEEE 802.16e compliantwireless devices without requiring any changes to either the IEEE802.16e standard, the Network Architecture as defined by the WiMAXForum, the mobile devices themselves or the over the air controlmessages exchanged between the device and the network.

SUMMARY OF THE INVENTION

It is to be understood that both the following summary and the detaileddescription are exemplary and explanatory and are intended to providefurther explanation of the invention as claimed. Neither the summary northe description that follows is intended to define or limit the scope ofthe invention to the particular features mentioned in the summary or inthe description.

This invention provides a method, system and apparatus for controllingmobility on a wireless network, which includes retrieving a networkmobility preference, the network mobility preference indicating a levelof mobility service for the mobile station, the level of mobilityservice indicating the extent to which the mobile station can handoffamong base stations of the wireless network, and establishing a level ofmobility service for the mobile station based on the retrieved networkmobility preference.

In accordance with one aspect, the present invention provides a methodfor controlling mobility on a wireless network, the method includesretrieving a network mobility preference, the network mobilitypreference indicating a level of mobility service for the mobilestation, the level of mobility service indicating the extent to whichthe mobile station can handoff among base stations of the wirelessnetwork, and establishing a level of mobility service for the mobilestation based on the retrieved network mobility preference.

In accordance with another aspect, the present invention provides anapparatus for controlling mobility on a wireless network, the apparatusincludes a mobility disabling control module, the mobility disablingcontrol module configurable to restrict mobility of a mobile station inthe wireless network by using a network mobility preference to establisha level of mobility service for a mobile station based on the networkmobility preference.

In accordance with yet another aspect, the present invention provides agateway for controlling mobility on a wireless network, which includes amemory for storing data from corresponding to at least one networkmobility preference; and a processor, the processor operates to receivea handoff request message from a network device, to analyze the handoffrequest message to determine a level of mobility service to assign to amobile station and to establish a level of mobility service for themobile station based on the network mobility preference.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention, and theattendant advantages and features thereof, will be more readilyunderstood by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings wherein:

FIG. 1 is a block diagram of the network architecture of a communicationnetwork constructed in accordance with the principles of the presentinvention;

FIG. 2 is a block diagram of a first operational embodiment of thepresent invention;

FIG. 3 is a sequence diagram illustrating a mobile station initiatedhandoff process;

FIG. 4 is a sequence diagram illustrating a network (base station)initiated handoff process;

FIG. 5 is a sequence diagram illustrating a mobile station reactivehandoff process;

FIG. 6 is a sequence diagram illustrating a location update process;

FIG. 7 is a sequence diagram illustrating a network initiated idle modeexit process; and

FIG. 8 is a sequence diagram illustrating a mobile station initiatedidle mode exit process.

DETAILED DESCRIPTION OF THE INVENTION

This invention provides a method, system and apparatus for controllingmobility in a wireless network that deploys the air interface defined bythe Institute of Electrical and Electronics Engineers (“IEEE”) 802.16estandard, and the corresponding worldwide interoperability for microwaveaccess (“WiMAX”) network architecture standard as defined by the WiMAXForum.

Referring now to the drawing figures in which like reference designatorsrefer to like elements, there is shown in FIG. 1, a system constructedin accordance with the principles of the present invention anddesignated generally as “10.” System 10 includes base stations 12 (“BS”)and mobile stations 14 (“MS”). Base stations 12 engage in wirelesscommunication with mobile stations 14. Similarly, mobile stations 14engage in wireless communication with base stations 12.

Base station 12 can be any base station arranged to wirelesslycommunicate with mobile stations 14. Base stations 12 include thehardware and software used to implement the functions described hereinto support the MAC control plane functions. Base stations 12 include acentral processing unit, transmitter, receiver, I/O devices and storagesuch as volatile and nonvolatile memory as may be needed to implementthe functions described herein.

Mobile stations 14 can be any mobile station including but not limitedto a computing device equipped for wireless communication, cell phone,wireless personal digital assistant (“PDA”) and the like. Mobilestations 14 also include the hardware and software suitable to supportthe MAC control plane functions needed to engage in wirelesscommunication with base station 12. Such hardware can include areceiver, transmitter, central processing unit, storage in the form ofvolatile and nonvolatile memory, input/output devices, etc.

FIG. 2 shows system 10 with an access service network gateway 18 (“ASNGW”) in communication with base stations 12A, 12B in accordance with theprinciples of the invention (base stations 12A and 12A are referred tocollectively herein as “base stations 12”). The ASN GW 18 provides anaggregation of control plane functions, e.g., mobility, in addition toperforming bearer plane routing or bridging functions. The ASN gateway18 includes the hardware and software suitable to support the MACcontrol plane functions used to engage in communication with basestations 12. Such hardware can include protocol translators, impedancematching devices, rate converters, fault isolators, or signaltranslators as necessary to provide system interoperability. Moreimportantly, the ASN GW 18 provides a number of options for allowingmobility between base stations 12. For example, ASN GW 18 allows systemoperators to select “no mobility” “partial mobility” and “full mobility”options, which are selectable at the ASN GW level to restrict or controlmobility support for IEEE 802.16e compliant wireless mobile stations 14.These options are functionally implemented within ASN GW 18 as describedbelow.

In another embodiment, it may be desirable to restrict mobility from anybase station to any other base station. Other examples of restrictingmobility would include but are not limited to restricting mobility togroups of base stations (e.g., paging groups) with no particulargeographical significance, or for those base stations within certaingeographical boundaries. Additionally, mobility may be restricted basedon “no-mobility” being explicitly configured on the mobility disablingcontrol module. Other examples of criteria for no mobility would be timeof day constraints, network (or base station) load, users subscriptionprofile, and the like.

As shown in FIG. 2, mobile station 14 engages in bidirectionalcommunication with base stations 12, which have overlapping coverageregions 22A, 22B respectively. The ASN GW 18 supports interfaces such asthe WiMAX network reference architecture R6 interfaces, which implementa set of control and bearer plane protocols for communication betweenthe base stations 12 and the ASN GW 18. The bearer plane includes anintra-ASN data path or inter-ASN tunnel between the base stations 12 andthe ASN GW 18. The control plane includes protocols for IP tunnelmanagement (establish, modify and release) in accordance with the mobilestation 14 mobility events. The ASN GW 18 to base stations 12 interfacemay also serve as a conduit for exchange of media access control (“MAC”)layer state information between neighboring base stations 12. The ASN GW18 to mobile station 14 interface may include additional protocolsrelated to the management plane.

In this embodiment, a mobility disabling control module 20 (“MDC”) iscoupled to the ASN GW 18 and provides the communications network system10 with the capability to control the mobility service by implementingemploying a MAC layer 2 handoff manager on the ASN GW 18. For example,when there is a requirement that mobility be fully restricted incommunications network system 10, the layer 2 handoff manager isnotified by the MDC module 20 that mobility is to be disabled, and thehandoff manager of ASN GW will reject any handoff requests from mobilestation 14, base stations 12 and or both mobile station 14 and basestations 12. In this way, the MDC module 20 provides a configurablefeature that can control the decision-making process associated with thehandoff manager of the ASN GW 18. In other words, the MDC module 20 canbe seen as providing a way to implement a configurable mobilitypreference that indicates a level of mobility service a mobile station14 is to have in a particular network. The MDC module 20 can be asoftware implementation, a hardware implementation or a combination ofboth.

Many of the functional units described in this specification have beenlabeled as modules, in order to more particularly emphasize theirimplementation independence. For example, a module may be implemented asa hardware circuit comprising custom circuits or gate arrays,off-the-shelf semiconductors such as logic chips, transistors, or otherdiscrete components. A module may also be implemented in programmablehardware devices such as field programmable gate arrays, programmablearray logic, programmable logic devices or the like.

Modules may also be implemented in software for execution by varioustypes of processors. An identified module of executable code may, forinstance, comprise one or more physical or logical blocks of computerinstructions, which may, for instance, be organized as an object,procedure, or function. Nevertheless, the executables of an identifiedmodule need not be physically located together, but may comprisedisparate instructions stored in different locations which, when joinedlogically together, comprise the module and achieve the stated purposefor the module.

A module of executable code could be a single instruction, or manyinstructions, and may even be distributed over several different codesegments, among different programs, and across several memory devices.Similarly, operational data may be identified and illustrated hereinwithin modules, and may be embodied in any suitable form and organizedwithin any suitable type of data structure. The operational data may becollected as a single data set, or may be distributed over differentlocations including over different storage devices, and may exist, atleast partially, merely as electronic signals on a system or network.

An operational embodiment of the present invention is described withreference to FIG. 3. FIG. 3 illustrates a timing diagram of a mobilestation 14 initiated handoff in an access service network (“ASN”) thathas had mobility disabled. The source or serving base station 12A(“SBS”) and the target base station 12B (“TBS”) are in communicationwith the ASN GW 18. The mobile station 14 initiates the handoff processby sending a handoff request message, such as the IEEE 802.16e definedMOB_MSHO-REQ to its current SBS12A, indicating a list of potential basestation(s) to which the mobile station 14 seeks a handoff (Step S100).SBS12A receives the handoff request from mobile station 14 and sends ahandoff request, such as the WiMAX networking group (“NWG”) definedR6_HO-REQ to the layer 2 handoff manager of ASN GW 18 (Step S102).Because mobility is disabled on ASN GW 18, the handoff manager on theASN GW 18 rejects the handoff request from serving base station 12A bysending a response message, such as WiMAX NWG defined R6_HO-RSP to theserving base station 12A. The rejection can be communicated to servingbase station 12A by omitting to include any recommended base station inthe response message (e.g., R6_HO-RSP) and/or by using an explicitreject type-length-value (“TLV”) element in the message (Step S104). AtStep S108, the serving base station 12A responds to the mobile station14 with a message, e.g., an IEEE 802.16e defined MOB_BSHO-RSP messageindicating that the handoff to selected base station 12B is notrecommended, e.g., with mode equal to “0b111”. At this point, the mobilestation 14 may reconfigure the base station list and sent anothermobility handoff request, such as the IEEE 802.16e defined MOB₁₃MSHO-REQ.

Referring to FIG. 4, with respect to serving base station 12A, theserving base station 12A initiates a handoff request for mobile station14, such as the WiMAX NWG defined R6_HO-REQ to the layer 2 handoffmanager of ASN GW 18 (Step S110). Since mobility is disabled on ASN GW18, the handoff manager on the ASN GW 18 rejects the handoff request bysending a corresponding rejection message such as the WiMAX NWG definedR6_HO-RSP response to the serving base station 12A. The rejection can becommunicated to serving base station 12A by omitting to include anyrecommended base station data in the rejection message (R6_HO-RSP)and/or by using an explicit reject TLV element in the message (StepS112). Since the handoff response message from the ASN-GW 18 (e.g.,R6_HO-RSP response) signaled a rejection, the serving base station 12Awill not initiate a network handoff by sending an appropriate message,e.g., an IEEE 802.16e defined MOB_BSHO-REQ. Alternatively, the MDCmodule 20 can be configured to provide partial disablement of mobilityservice conditioned upon which network element initiates the handoffrequest. For example, in the event that the mobile station 14 initiatesa handoff request, then mobility is always disabled, however, if a basestation 12A, 12B initiates the handoff request, then the layer 2 handoffmanager of ASN GW 18 will permit the handoff to occur.

Referring to FIG. 5, with respect to mobile station 14, the mobilestation 14 initiates a reactive handoff request by sending a rangingrequest, e.g., the IEEE 802.16e defined RNG-REQ message, to a targetbase station 12B (Step S120). In this case, the ranging request is sentto indicate the mobile station's re-entry into the network 10. Thetarget base station 12B sends a context request message, e.g., the WiMAXNWG defined Context-REQ, to ASN GW 18 and requests the mobile station'scontext information (Step S122). Because mobility is disabled on thesystem 10, the ASN GW 18 replies with a context response withoutincluding any of the context information (Step S124) for mobile station14. At Step S126, the target base station 12B sends a contextacknowledgement message, e.g., the WiMAX NWG defined Context-ACK, toacknowledge the context-response from ASN GW 18. When the ASN GW 18receives a context acknowledgement message, such as the WiMAX NWGdefined Context-ACK, an “accounting stop” can be sent to an AAAaccounting server (not shown) to stop additional charges by the previousbase station 12 to the mobile station 14 account. Upon receiving thecontext response message without the mobile station 14 contextinformation, target base station 12B sends a ranging response message,such as the IEEE 802.16e defined RNG-RSP to the mobile station 14 (StepS128). Since the base station 12B did not receive any mobile station 14context information, it can neither include any connection identifier(“CID”) update message, e.g., CID-UPDATE TLV, in the ranging responsenor handoff optimization messages e.g., TLVs to the mobile station 14.As a result, the mobile station 14 is unable to conduct a mobile handoffto the target base station 12B and the call terminates. This means thatin order for mobile 14 to establish network connectivity it must performa full network reentry. Accordingly, once mobile station 14 receives theranging request (RNG-RSP) from the base station 12B, and that rangingrequest is without any optimization TLV or a CID-UPDATE TLV, the mobilestation 14 will perform network entry procedures.

In general, the procedures that a mobile station 14 performs whenentering a network includes performing basic capability negotiations viathe exchange of subscriber station basic capability (“SBC”) request andSBC response with the network. Next, authentication and authorization ofthe mobile station 14 is performed and the exchange of registrationrequest and registration response with the network is completed. Anegotiation for security keys occurs and the network can set up theservice flows, which are the connections by which information packetsare transmitted and received to complete the entry procedures (StepS130). At Step S132, the re-entry into the system 10 by mobile station14 is complete.

Referring to FIG. 6, with respect to mobile station 14, the mobilestation 14 is forced to perform a full network re-entry from idle modeif location update (“LU”) is performed via a base station other than thebase station through which the mobile station either entered idle modeor performed a successful location update. FIG. 6 illustrates a mobilestation 14 initiating a location update by sending a ranging request,e.g., RNG-REQ to a target base station 12B (Step S140). The target basestation 12B sends a location update request message, e.g., LU-REQ, tothe paging controller of the ASN GW 18 and requests location update(Step S142). Because mobility is disabled on the network and thelocation update request is coming from a new base station 12B, the ASNGW 18 paging controller replies with a location update response withoutany of the context information for mobile station 14 (Step S144). Uponreceiving the location update response without mobile station 14 contextinformation, target base station 12B sends a ranging response message,e.g., RNG-RSP message to the mobile station 14 indicating that locationupdate failed, e.g., location update response equal to “failure” (StepS146). At Step S148, the target base station 12B sends a location updateconfirmation, e.g., LU-Confirm to acknowledge the LU-response frompaging controller of ASN GW 18. Once mobile station 14 receives theranging response message, e.g., RNG-RSP without any handoff optimizationTLV, the mobile station 14 will perform all network entry procedures asdiscussed previously with respect to FIG. 5 and Step S130. At Step S150,the mobile station 14 can send a subscriber base station capabilitiesrequest, e.g., SBC-REQ to commence the network re-entry process.

Referring to FIG. 7, with respect to mobile station 14, the mobilestation 14 is forced to perform a full network re-entry from idle modeif the network initiates a network idle mode exit page in order totransmit a downlink packet received on behalf of the idle mobile station14, when the mobile station 14 has moved into a coverage area of a newbase station 12B. FIG. 7 illustrates an ASN GW 18 initiating a pagingannouncement to all base stations 12 in mobile station's 14 currentpaging group without any of mobile station's 14 context information(Step S160). The serving and target base stations 12 receiving thepaging announcement will page the mobile station 14 by sending out amobile paging advertisement, e.g., MOB_PAG-ADV, to the mobile station 14to inform it to re-enter the network (Step S162). Mobile station 14re-enters the network at one of the base stations 12 by sending aranging request, e.g., RNG-REQ with ranging purpose set to re-entry fromidle mode (Step S164). New serving base station 12B sends a contextrequest e.g., CONTENT-REQ to obtain mobile station's 14 context from thepaging controller (“PC”) of ASN GW 18 (Step S166). Since mobility isdisabled by the ASN GW 18, the paging controller determines that mobilestation 14 has moved to a different base station 12B and sends aContext-Response without any of mobile station's context information(Step S168).

Upon receiving the location update response without mobile station's 14context information, at Step S170, new serving base station 12B sends aranging response message, e.g., RNG-RSP message without any handoffoptimization TLV or CID-UPDATE TLV to the mobile station 14 informingthe mobile station 14 to perform all network entry procedures asdiscussed previously with respect to FIG. 5 and Step S130. At Step S172,the new serving base station 12B sends a content acknowledgementmessage, e.g., CONTENT-ACK, to acknowledge the content response frompaging controller of ASN GW 18. At Step S174, the mobile station 14 willperform all network entry procedures as discussed previously withrespect to FIG. 5 and Step S130. At Step S176, the mobile station's 14re-entry into the network is complete.

Referring to FIG. 8, with respect to mobile station 14, the mobilestation 14 is forced to perform a full network re-entry when the mobilestation 14 attempts idle mode exit via a base station 12B other than theone at which the mobile station 14 either entered idle mode or performeda successful location update. FIG. 8 illustrates a mobile station 14initiating a location update by sending a ranging request, e.g.,RNG-REQ, to a target base station 12B indicating intention to re-enterthe network from the idle mode (Step S180). The target base station 12Bsends a context request message, e.g., CONTEXT-REQ, to the ASN GW 18 andrequests context information (Step S182). Because mobility is disabledon the network and the context request is coming from a new base station12B, the ASN GW 18 paging controller replies with a context response(“CONTEXT-RESPONSE”) without any of the mobile's context information(Step S144). Upon receiving the context response without mobile station14 context information, target base station 12B sends a rangingresponse, e.g., RNG-RSP message to the mobile station 14 without thehandoff optimization TLV and CID-UPDATE TLV (Step S16). At Step S148,the target base station 12B sends a context acknowledgement message,e.g., Content-ACK, to acknowledge the Content-response from pagingcontroller of ASN GW 18. Once mobile station 14 receives the rangingresponse, e.g., RNG-RSP without any handoff optimization TLV, the mobilestation 14 will perform all network entry procedures as discussedpreviously with respect to FIG. 5 and Step S130. At Step S190, themobile station 14 will perform all network entry procedures as discussedpreviously with respect to FIG. 5 and Step S130. At Step S192, mobilestation's 14 re-entry into the network is complete.

The present invention advantageously provides a method, system andapparatus for restricting full or partial mobility support for IEEE802.16e compliant wireless devices without requiring any changes to theIEEE 802.16e standard, the Network Architecture as defined by the WiMAXForum or the over the air control messages exchanged between thewireless device and the network by employing a mobility disablingcontrol module. By employing this improved mobility disabling controlscheme, the communication network operator can comply with governmentalregulations without having to revert to costly replacement systems. Ofcourse, it is understood that the present invention is not limited toIEEE 802.16e compliant wireless networks and that the invention can beimplemented in any wireless network that includes the ability to handoff communications with a wireless device among different base stations.

The present invention can be realized in hardware, software, or acombination of hardware and software. An implementation of the methodand system of the present invention can be realized in a centralizedfashion in one computing system or in a distributed fashion wheredifferent elements are spread across several interconnected computingsystems. Any kind of computing system, or other apparatus adapted forcarrying out the methods described herein, is suited to perform thefunctions described herein.

A typical combination of hardware and software could be a specialized orgeneral-purpose computer system having one or more processing elementsand a computer program stored on a storage medium that, when loaded andexecuted, controls the computer system such that it carries out themethods described herein. The present invention can also be embedded ina computer program product, which comprises all the features enablingthe implementation of the methods described herein, and which, whenloaded in a computing system is able to carry out these methods. Storagemedium refers to any volatile or non-volatile storage device.

Computer program or application in the present context means anyexpression, in any language, code or notation, of a set of instructionsintended to cause a system having an information processing capabilityto perform a particular function either directly or after either or bothof the following a) conversion to another language, code or notation; b)reproduction in a different material form. In addition, unless mentionwas made above to the contrary, it should be noted that all of theaccompanying drawings are not to scale. Significantly, this inventioncan be embodied in other specific forms without departing from thespirit or essential attributes thereof, and accordingly, referenceshould be had to the following claims, rather than to the foregoingspecification, as indicating the scope of the invention.

It will be appreciated by persons skilled in the art that the presentinvention is not limited to what has been particularly shown anddescribed herein above. A variety of modifications and variations arepossible in light of the above teachings without departing from thespirit or essential attributes thereof, and accordingly, referenceshould be had to the following claims, rather than to the foregoingspecification, as indicating the scope of the of the invention.

What is claimed is:
 1. A method of limiting mobility provided to amobile station by a wireless network, the method comprising: when themobile station moves from a first service region served by a first basestation to a second service region served by a second base station inthe wireless network, preventing, by a processor coupled to the wirelessnetwork, hand-off of the mobile station from the first base station tothe second base station based on at least one mobility preference of thewireless network, wherein the at least one mobility preference comprisesrejection of all handoff requests from the mobile station; enablingnetwork re-entry of the mobile station in the second service regionserved by the second base station.
 2. The method of claim 1, wherein thefirst service region is served by a first plurality of base stationsincluding the first base station, wherein the at least one mobilitypreference comprises partially restricted mobility, and wherein themobile station is permitted, by the processor, to hand-off between basestations of the first plurality of base stations based on the partiallyrestricted mobility.
 3. The method of claim 1, wherein the at least onemobility preference comprises rejection of a request to hand-off themobile station from the first base station to the second base station.4. The method of claim 1, wherein the at least one mobility preferencecomprises rejection of a request to hand-off the mobile station from thefirst base station to the second base station, and wherein the rejectionis sent to the first base station.
 5. The method of claim 1, whereinenabling network re-entry of the mobile station in the second servicearea served by the second base station comprises: receiving, by theprocessor, a request for re-entry of the mobile station in the secondservice region; and sending, by the processor, a response permittingre-entry of the mobile station in the second serving region.
 6. Themethod of claim 1, wherein enabling network re-entry of the mobilestation comprises: receiving, by the processor, a request for re-entryof the mobile station in the second service region, wherein the requestfor re-entry is received from the second base station; and sending, bythe processor, a response permitting re-entry of the mobile station inthe second serving region, wherein the response is sent to the secondbase station.
 7. The method of claim 1, wherein enabling networkre-entry of the mobile station comprises: receiving, by the processor, arequest for re-entry of the mobile station in the second service region,wherein the request comprises a context request; and sending, by theprocessor, a response permitting re-entry of the mobile station in thesecond serving region, wherein the response comprises a contextresponse.
 8. The method of claim 1, wherein enabling network re-entry ofthe mobile station comprises: receiving, by the processor, a request forre-entry of the mobile station in the second service region, wherein therequest comprises a location update request; and sending, by theprocessor, a response permitting re-entry of the mobile station in thesecond serving region, wherein the response comprises a location updateresponse.
 9. The method of claim 1, wherein the wireless network is anIEEE 802.16-compliant network.
 10. An apparatus for limiting mobilityprovided to a mobile station by a wireless network when the mobilestation moves from a first service region served by a first base stationto a second service region served by a second base station, theapparatus comprising: a wireless network interface configured to receivemessages from the wireless network and send messages to the wirelessnetwork; and a control module coupled to the wireless network interface,the control module being configured to: prevent hand-off of the mobilestation from the first base station to the second base station based onat least one mobility preference of the wireless network, wherein the atleast one mobility preference of the wireless network comprisesrejection of all handoff requests from the mobile station; and enablenetwork re-entry of the mobile station in the second service regionserved by the second base station.
 11. The apparatus of claim 10,wherein the at least one mobility preference comprises partiallyrestricted mobility and when the first service region is served by afirst plurality of base stations including the first base station, thecontrol module being further configured, to permit the mobile station tohand-off between base stations of the first plurality of base stationsbased on at least the mobility preference of partially restrictedmobility.
 12. The apparatus of claim 10, wherein the at least onemobility preference comprises rejection of a request to hand-off themobile station from the first base station to the second base station,and the control module is configured to send the rejection.
 13. Theapparatus of claim 10, wherein the at least one mobility preferencecomprises rejection of a request to hand-off the mobile station from thefirst base station to the second base station, and wherein the controlmodule is configured to send the rejection to the first base station.14. The apparatus of claim 10, wherein the control module is furtherconfigured to: enable the network re-entry of the mobile station in thesecond service area served by the second base station by receiving arequest for re-entry of the mobile station in the second service region;and send a response permitting re-entry of the mobile station in thesecond serving region.
 15. The apparatus of claim 10, wherein thecontrol module is further configured to: enable the network re-entry ofthe mobile station in the second service area served by the second basestation by receiving a request for re-entry of the mobile station in thesecond service region, wherein the request for re-entry is received fromthe second base station; and send a response permitting re-entry of themobile station in the second serving region, wherein the response issent to the second base station.
 16. The apparatus of claim 15, whereinthe request is a context request, and the response is a contextresponse.
 17. The apparatus of claim 15, wherein the request is alocation update request, and the response is a location update response.18. The apparatus of claim 10, wherein the wireless network interface isIEEE 802.16-compliant for operation with an IEEE 802.16-compliantwireless network.
 19. The method of claim 1, wherein the at least onemobility preference comprises load of the wireless network.
 20. Theapparatus of claim 10, wherein at least one mobility preferencecomprises a load of the wireless network.
 21. The method of claim 1,wherein at the least one mobility preference includes allowing handoffwhen one or more of the bases stations initiates the hand-off request.